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Stress relieving is a form of post weld heat treatment. In stress relieving we heat a material to a specific temperature; hold it at this temperature for a specified amount of time in order to reduce or eliminate residual stresses; and then cool it at a slow enough rate to prevent these stresses from redeveloping. […]

What is it? Why is PWHT needed? How is PWHT done?

Have you heard of post weld heat treatment (PWHT)? Of course you have. If you are involved in welding you have definitely heard this term. But what is PHWT? When is PWHT required? What temperature should PWHT be done at? Heat treating of materials can be a very complicated subject, but when it comes to […]

If you have welded aluminum you know that it behaves considerably different than steel. Other than the strength difference and general appearance, there are four physical characteristics of aluminum that make it weld completely different than steel. These are: High thermal conductivity High solidification shrinkage High hydrogen solubility Oxide coating When welding aluminum it is […]

Getting deeper penetration, or at least adequate penetration is very important in welding. There are a few applications in which we wish to minimize penetration, but in general we always want good penetration. There are many variables that affect penetration, some more than others. It is important to know how each individual variable affects the […]

When it comes to fillet welds, bigger is not always better. A fillet weld is easy to measure, simply take out your fillet weld gauges measure it. However, there is an incorrect assumption that a bigger weld (as measured with a fillet gauge) is always stronger than a smaller weld. Before we get into this […]

Preheat is used when a base material, due to its chemical composition, thickness or level or restraint, is susceptible to cold cracking. Knowing what temperature to preheat your base metal is sometimes a complicated matter. You may hear people say “preheat to 300F to be safe.” The reality is that 300F may be playing it […]

Porosity is a weld discontinuity that is not as detrimental to structural integrity as cracks, undercut, overlap and lack of fusion. However, it is unsightly and when painted it looks absolutely horrible. Because it does not have sharp ends, porosity does not propagate like a crack. The reason why there are limits to the amount […]

Prequalified welding procedures are a great tool available to those who need qualified procedures in conformance with AWS D1.1 Structural Welding Code – Steel. However, there are strict requirements for the use of a prequalified welding procedures. It is not as easy as picking a qualified joint and using filler metal manufacturer’s recommended procedures. There […]

Most types of stainless steels have good weldability and can be welded with all arc welding processes (GMAW, FCAW, GTAW, SMAW and SAW). This is both good and bad. It’s good because it makes fabrication possible, but it’s bad because most assume it can be welded just like carbon steel. In fact, this is the […]

How to store stick electrodes, and mig, flux-cored and metal-cored wires

Proper storage of both opened and unopened packages of welding consumables is crucial. It should avoid quality issues such as porosity, excessive slag fluidity, rough weld surface, difficult slag removal and more importantly, elevated levels of diffusible hydrogen which can lead to cracking. Adequate storage, handling and re-conditioning of electrodes vary according to type. The […]